Illumination- and Annealing-Induced Changes in the Infrared and Raman Spectra of a-Si:H

2001 ◽  
Vol 664 ◽  
Author(s):  
L.-F. Arsenault ◽  
S. Lebiba ◽  
E. Sacher ◽  
A. Yelon

ABSTRACTWe have investigated the changes, produced by light-soaking, in both the IR and Raman responses of the Si-Hn stretching peaks in the 2000-2100 cm−1 range. Our observations of the IR response are in qualitative agreement with those of Kong and co-workers [1]: that is, short-term light soaking produces an increase in the intensity of the signal and a simultaneous shift to lower frequency. In contrast, short-term light soaking decreases the total intensity of the Raman signal in the 2000-2100 cm−1 range, when normalized to the TO phonon peak at about 480 cm−1. In both cases, these modifications are reversed on annealing at 200° C. We suggest that these changes are attributable to alterations in the environments of the Si-Hn bonds, with the resultant transfer of intensity between IR and Raman matrix elements. Details of the evolution of the components of the Raman spectrum in the 2000-2100 cm−1 range are presented, and compared with IR changes in the same range.

1971 ◽  
Vol 25 (2) ◽  
pp. 182-186 ◽  
Author(s):  
J. R. Durig ◽  
S. J. Meischen ◽  
S. E. Hannum ◽  
R. R. Hitch ◽  
S. K. Gondal ◽  
...  

The ir spectra of (CH3)3SiCo(CO)4 in the gaseous (4000–250 cm−1) and solid (4000–33 cm−1) phases have been recorded. The Raman spectrum has also been recorded for the solid state. To aid in the assignment, the ir and Raman spectra were recorded of solid (CH3)3SiH. The vibrational assignment for most of the 60 normal modes has been given on the basis of the fundamental vibrations of the –Si(CH3)3 and –Co(CO)4 moities. The static field was sufficiently strong to split the degenerate modes but the correlation field was so weak that no definite splitting of the symmetric modes was detected.


1961 ◽  
Vol 39 (11) ◽  
pp. 2171-2178 ◽  
Author(s):  
R. J. Gillespie ◽  
E. A. Robinson

New assignments are proposed for the fundamental frequencies of SOF2, SOCl2, SO2Cl2, SO2F2, and SO2FBr, based on new measurements of the Raman spectrum of SO2Cl2 and previous measurements of the infrared and Raman spectra of these molecules. The fundamental frequencies of these molecules are found to be related to each other and to those of similar molecules when the normal modes are described in terms of characteristic vibrations of the SO, SO2, S(Hal), and S(Hal)2 groups.


1964 ◽  
Vol 42 (9) ◽  
pp. 2107-2112 ◽  
Author(s):  
W. K. Busfield ◽  
M. J. Taylor ◽  
E. Whalley

The infrared spectrum in the range 3000–50 cm−1 and the Raman spectrum of solutions of dithiophosgene have been obtained. There are no coincidences in the infrared and Raman spectra, and the only structure consistent with this and approximately tetrahedral carbon valencies is[Formula: see text]that is tetrachloro-1,3-dithietane, in which the ring is planar or nearly planar. A tentative assignment of the observed bands is given on the basis of D2h symmetry.


2019 ◽  
Vol 70 (1) ◽  
pp. 107-111
Author(s):  
Imirela Nicolov ◽  
Doina Georgescu ◽  
Emiliana Laura Andreici Eftimie ◽  
Simona Cinta Pinzaru ◽  
Roxana Roman ◽  
...  

Combined experimental and theoretical studies on molecular structure of the betulinic acid solvatomorph of ethanol, 2-butanol and isopropyl alcohol solvents, grown by recrystallization method, are reported. Theoretical investigations, in the frame of DFT, are done using the new method of the betulinic acid solvatomorph molecule extraction from the corresponding molecular crystal, based on typical fragmentation scheme and chemical connectivity. For all electrons, a localized basis set of Gaussian type functions TZVP and local gradient corrected functional BP86 were used. Good correlation was found between the calculated and experimental data. Slight differences in the lattice modes spectral range (0-200 cm-1) from experimental Raman spectra suggest slight differences in the crystalline network and highlight the powerful Raman approach in evidencing BA pseudo-polymorphs or solvatomorphs. Data obtained suggest that incorporated solvents to the solvates generaly induced changes in crystal symmetry, intermolecular arrangements, stoichiometry and hydrogen bonding interactions of the analysed solvatomorphs.


1985 ◽  
Vol 40 (5) ◽  
pp. 594-600 ◽  
Author(s):  
Ralf Steudel ◽  
Torsten Sandow ◽  
Jürgen Steidel

Abstract The homocyclic oxides S9O (m.p. 33 °C, dec.) and S10O (m.p. 51 °C, dec.) have been prepared by oxidation of the corresponding sulfur rings S9 and S10 , respectively, by trifluoroperoxy acetic acid (molar ratio 1:2-3) in a carbon disulfide/methylene chloride mixture. According to infrared and Raman spectra, both compounds contain an exocyclic oxygen atom. S9O and S10O decompose at 25 °C to give SO2 and a polysulfuroxide SnO with >10 but both can be stored at -78 °C without decomposition. The SS bond distances are discussed on the basis of the Raman spectra. In addition, the Raman spectrum of solid S9 has been recorded for the first time. It shows that S9 crystallizes as two allotropes (α-and β-S9) both consisting of cyclic molecules of either C1 or C2 symmetry with bond distances of between 203 and 209 pm.


1989 ◽  
Vol 44 (1) ◽  
pp. 74-78 ◽  
Author(s):  
G. Kliche ◽  
H. G. von Schnering

Abstract Infrared and Raman spectra of the metal cluster compound [Nb6F12]F3 (cubic Im3̄m; Z = 2) are reported. The three intense m odes observed in the Raman spectrum at 215. 267, and 337 cm-1 and a weak mode observed in the infrared spectrum at 287 cm-1 are assigned to the T2g, Eg, A1g, and T1u vibrational modes of the Nb6 octahedra. The assignment is supported by normal coordinate analysis and Raman measurements at 47 kbar. The valence force constants are f(Nb-Fi) = 2.04, f(Nb-Fa-a) = 1.30 and f(Nb-Nb) = 0.97 N cm-1 metal-to-metal interaction in the cluster.


1985 ◽  
Vol 50 (2) ◽  
pp. 306-316 ◽  
Author(s):  
Blanka Vlčková ◽  
Bohuslav Strauch ◽  
Milan Horák

Infrared and Raman spectra of Cu(II) bis(2,4-pentandionate) and Pd(II) bis(2,4-pentandionate) complexes have been measured and interpreted. The coincidence of numerous bands in the IR and Raman spectra has been explained by the isolation effect of the heavy central metal atom which prevents the vibrational interaction of the two ligands in the chelate molecule with each other. An 11-particle model consisting of all the atoms of one ligand (both CH3 groups are taken as the point masses), a central metal atom and two oxygen atoms of the other ligand has been proved to be most adequate for the empirical interpretation of the spectra.


1970 ◽  
Vol 24 (6) ◽  
pp. 601-605 ◽  
Author(s):  
R. Foglizzo ◽  
A. Novak

The ir and Raman spectra of pyrazinium chloride and bromide and their ND deuterated derivatives have been obtained in the 4000–300 cm−1 range. Twenty-six fundamentals of the pyrazinium ion are identified and compared to those of the pyrazine molecule. Frequency shifts on protonation of pyrazine are discussed.


2015 ◽  
Vol 34 (1) ◽  
pp. 87 ◽  
Author(s):  
Sofija Lazarevska ◽  
Petre Makreski

<p>            In terms of chemical composition, a honeybee secretion known as royal jelly (RJ) is very complex product containing water, proteins, carbohydrates, lipids, mineral salts and small amounts of polyphenols, vitamins and enzymes. Despite its chemical diversity, the bands originating from vibrational modes of the present proteins were successfully assigned in 1800–1200 cm<sup>–1</sup> (Raman and IR) region where the interference of bands from other vibrational species is not substantial. The protein bands were attributed to amide I, amide II and amide III modes and their intensities, additionally, enabled to determine the protein secondary structures. The remaining bands up to 4000 cm<sup>–1</sup> were attributed to other group vibrations whereas the region below 1200 cm<sup>–1 </sup>comprises bands from complex interacting modes within the major RJ components that can not be unequivocally attributed to distinct modes. The work also represents a pioneering effort to collect and interpret the Raman spectrum of fresh and lyophilized RJ samples and to correlate and describe the observed similarities/differences between IR and Raman spectra.</p>


Sign in / Sign up

Export Citation Format

Share Document